1. Field of the Invention
The present invention is generally related to a cooling system for a marine propulsion device and, more particularly, to an open cooling system that automatically drains when the marine vessel is taken out of the water.
2. Description of the Related Art
Those skilled in the art of marine propulsion systems are well aware of many different types of cooling systems used to remove heat from components of the marine propulsion system. Some marine propulsion devices use an open cooling system, in which water is drawn from a body of water and circulated through the system in thermal communication with heat emitting devices, while other systems are closed systems, or partially closed systems, in which a coolant, such as ethylene glycol, is circulated in thermal communication with the heat emitting portions of those components. The partially closed systems normally use a liquid-to-liquid heat exchanger that circulates the ethylene glycol in thermal communication with water that is drawn from the body of water in which the marine vessel operates. In either type of cooling system, it is significantly beneficial if the water which is drawn from the body of water can be easily and quickly removed from the cooling system when the marine vessel is taken out of the water. The act of draining this water from the cooling system sometimes requires the operator of the marine vessel to perform numerous tasks. The degree of complexity required to drain the cooling system of a marine vessel can vary from relatively simple to highly complex. However, cooling systems for marine vessels typically require at least a minimum of manual intervention to cause the water to drain from the internal cavities of the cooling system.
U.S. Pat. No. 2,466,525, which issued to Wilson on Apr. 5, 1949, describes a cooling device for power plants of boats. Saltwater is used as the cooling medium. As a result, it eliminates the necessity of using circulating pumps which are subject to a number of disadvantages. The device provides in the bottom of a boat a water circulating tank though which cold saltwater is passed and also through which the cooling medium is circulated to be cooled by the saltwater. An improved means for introducing cold saltwater is provided and it evacuates warmed or heated saltwater which has contacted the cooling medium of the power plant.
U.S. Pat. No. 4,741,715, which issued to Hedge on May 3, 1988, discloses a pressure actuated drain valve for a marine drive. The drain valve automatically drains the cooling water from a marine drive engine when the engine is stopped. The drain valve includes a spring-loaded diaphragm which moves to a closed position when the engine water pump is operating to close an outlet from the engine cavities to be drained. The diaphragm automatically moves to its open position when the engine water pump is off to open the outlet to allow cooling water to drain from the engine cavities.
U.S. Pat. No. 5,334,063, which issued to Inoue et al. on Aug. 2, 1994, describes a cooling system for a marine propulsion engine. The invention permits draining of the engine cooling jacket when it is not being run. In some embodiments, the drain valve also controls the communication of the coolant from the body of water in which the watercraft is operating with the engine cooling jacket. Various types of pumping arrangements are disclosed for pumping the bilge and automatic valve operation is also disclosed.
U.S. Pat. No. 5,628,285, which issued to Logan et al. on May 13, 1997, discloses a drain valve for a marine engine. The valve assembly automatically drains water from a cooling system of an inboard marine engine when the ambient temperature drops to a preselected value. The drain valve includes a cup-shaped base having a group of inlets connected to portions of a cooling system of the engine to be drained, and the open end of the base is enclosed by a cover. Each inlet defines a valve seat and a sealing piston is mounted for movement in the base and includes a series of valve members that are adapted to engage the valve seats. An outlet is provided in the side wall of the cup-shaped base. The valve members on the sealing piston are biased to a closed position by a coil spring and a temperature responsive element interconnects the sealing piston with the cover. The temperature responsive element is characterized by the ability to exert a force in excess of the spring force of the coil spring when the ambient temperature is above approximately 50 degrees Fahrenheit to thereby maintain the valve members in the closed position. When the temperatures falls below the selected temperature, the temperature responsive element will retract, thereby permitting the valve members to be open under the influence of the spring to automatically drain water from the cooling system of the engine.
U.S. Pat. No. 5,746,270, which issued to Schroeder et al. on May 5, 1998, discloses a heat exchanger for a marine engine cooling system. The cooling system is a closed loop cooling system. The heat exchanger body encloses a series of tubes carrying sea water which removes heat from the engine coolant. The heat exchanger includes an integrally connected top tank. A single venting orifice is provided into the top tank from the heat exchanger body. A heat exchanger coolant outlet is in direct fluid communication with both a system bypass and the coolant in the top tank. An auxiliary inlet for coolant from the top tank is located in the heat exchanger coolant outlet downstream of the bypass inlet, thereby promoting the ability of the system to draw coolant through the top tank rather than the bypass. The invention minimizes cavitation and reduces the creation of negative pressure at the circulating pump.
U.S. Pat. No. 5,902,159, which issued to Killpack et al. on May 11, 1999, describes an inboard/outboard motor cooling system winterizer. The device is intended for flushing or winterizing an inboard/outboard engine cooling system having an open basin for submerging cooling system intake portals in liquid. The basin is capable of being removably and sealably disposed about a sterndrive housing and allowing the sterndrive housing of the motor to pass through the bottom of the basin.
U.S. Pat. No. 5,966,080, which issued to Bigsby on Oct. 12, 1999, discloses a drain plug warning system. The system includes a first member that can be attached to a transom or other wall of a watercraft and a second member that is shaped to be received within an aperture that is formed through the first member. The drain water from the watercraft, the drain plug or second member is removed from the aperture of the first member, and water is allowed to drain through the aperture. If the second member is not replaced within the aperture to a predetermined location relative to the first member, a magnetically sensitive component near the aperture assumes a state that will cause an alarm under certain predefined conditions such as when an operator activates a key switch mechanism of the watercraft.
U.S. Pat. No. 5,980,342, which issued to Logan et al. on Nov. 9, 1999, discloses a flushing system for a marine propulsion engine. The system provides a pair of check valves that are used in combination with each other. One of the check valves is attached to a hose located between the circulating pump and the thermostat housing of the engine. The other check valve is attached to a hose through which fresh water is provided.
U.S. Pat. No. 6,050,867, which issued to Shields et al. on Apr. 18, 2000, discloses a drain system for a marine vessel. The system is provided for a marine vessel in which three types of drain operations can be performed at one common location near the transom of the marine vessel. A multiple conduit structure is provided with a plurality of fluid passages extending at least partially through the structure. A first fluid passage allows the bilge of the boat to be drained. A second fluid passage allows multiple locations on the engine to be drained through a common port. A second sealing plug is provided to close the second passageway that prevents fluid communication between the various fluid conduits used to drain the cooling water of the engine. A third fluid passage is provided through the multiple conduit structure to allow lubricating oil to be drained from the engine.
U.S. Pat. No. 6,089,934, which issued to Biggs et al. on Jul. 18, 2000, discloses an engine cooling system with a simplified drain and flushing procedure. The system is provided with one or more flexible conduits attached to drain openings of the engine and its related components. First ends of the conduits are attached to the drain openings while the second ends are sealed by studs attached to a plate of a stationary bracket. A retainer is slidably associated with the flexible conduits and attached to a tether which is, in turn, attached to a handle. By manipulating the handle, the tether forces the retainer to slide along the flexible conduits and control the position of second ends of the flexible conduits. This allows the system to be moved from a first position with the second ends of the conduits above the first ends of the conduits to a second position with the second ends of the conduits below the first ends and in the bilge of the boat. The system allows an operator to stand in a single location and move the drain system from the first and second position and back again without having to reach down into the engine compartment to remove drain plugs. The system allows the cooling system to be easily drained or flushed.
U.S. Pat. No. 6,135,064, which issued to Logan et al. on Oct. 24, 2000, discloses an engine drain system. An engine cooling system is provided with a manifold that is located below the lowest point of the cooling system of an engine. The manifold is connected to the cooling system of the engine, a water pump, a circulation pump, the exhaust manifolds of the engine, and a drain conduit through which all of the water can be drained from the engine.
U.S. Pat. No. 6,343,965, which issued to Biggs et al. on Feb. 5, 2002, discloses a pneumatically actuated marine engine water drain system. The system is provided which includes one or more pressure actuated valves associated with the coolant water drain system. The boat operator is provided with a pressure controller that allows pressure to be introduced into the system for the purpose of actuating the drain valves and, as a result, opening various drain conduits to allow cooling water to drain from the engine cooling system into the bilge or overboard.
U.S. Pat. No. 6,374,849, which issued to Howell on Apr. 23, 2002, describes a test cock apparatus with freeze protection capability. The apparatus is intended for controlling fluid pressure and flow in a backflow preventer valve. It includes a valve housing having interior walls defining a chamber therein and including an inlet port and a discharge port communicating with the chamber for permitting fluid flow therethrough. A temperature responsive freeze protection element is positioned within the chamber and is axially movable between a closed position in sealing engagement with the interior walls of the valve housing for preventing fluid flow through the discharge port and an open position out of sealing engagement with the walls of the valve housing for permitting passage of fluid through the discharge port.
U.S. Pat. No. 6,379,201, which issued to Biggs et al. on Apr. 30, 2002, discloses a marine engine cooling system with a check valve to facilitate draining. A marine engine cooling system is provided with a valve in which a ball moves freely within a cavity formed within the valve. Pressurized water, from a sea pump, causes the ball to block fluid flow through the cavity and forces pumped water to flow through a preferred conduit which may include a heat exchanger. When the sea pump is inoperative, the ball moves downward within the cavity to unblock a drain passage and allow water to drain from the heat generating components of the marine engine.
U.S. Pat. No. 6,390,870, which issued to Hughes et al. on May 21, 2002, discloses a marine engine cooling system with a simplified water drain and flushing mechanism. A manifold is located at a low portion of the cooling system to allow all of the water within the cooling system to drain through a common location, or manifold. A rigid shaft is connected to a valve associated with a manifold and extending upwardly from the manifold to a location proximate the upper portion of the engine so that a marine vessel operator can easily reach the upper end of the shaft and manipulate the shaft to open the valve of the manifold. In this way, the valve can be opened to allow all of the water to drain from the engine without requiring the marine vessel operator to reach toward locations at the bottom portion of the engine.
U.S. Pat. No. 6,439,939, which issued to Jaeger on Aug. 27, 2002, discloses a siphon inhibiting device for a marine cooling system. It comprises first and second portions of a housing structure and a buoyant member disposed within the housing structure for movement along a first axis between an inlet port and an outlet port. The buoyant member is shaped to have a cylindrical portion and another portion which is shaped in the form of a frustum of a cone. Upward movement of the buoyant member causes an elastomeric seal on the buoyant member to come into contact with an internal lip formed in the housing structure, thereby creating a seal that prevents an upward flow of water in a direction from the outlet port to the inlet port. When cooling water is drained from the outlet port area, the buoyant member is forced downwardly into an open position by its own weight and the weight of the water on its inlet port side. This free movement of the buoyant member allows the water on the inlet port side to drain without manual intervention. When normal flow occurs, in a direction from an inlet port to the outlet port, the buoyant member is forced downward into an open position and water flows around the buoyant member from a water pump toward the cooling system of the engine.
U.S. Pat. No. 6,506,085, which issued to Casey et al. on Jan. 14, 2003, discloses a pump and drain apparatus for a marine propulsion system. The apparatus is contained in a common housing structure to reduce the required space needed for these components in the vicinity proximate the engine of a marine propulsion system. The valve of the drain is remotely actuated by air pressure and therefore does not require the boat operator to manually remove plugs or manually actuate mechanical components to cause the engine to drain through a drain conduit that is formed as an integral part of the housing structure.
U.S. Pat. No. 6,582,263, which issued to Jaeger et al. on Jun. 24, 2003, discloses a marine exhaust elbow structure with enhanced water drain capability. The elbow is provided with a stainless steel tube within a water outlet opening to assure that a drain opening remains open even when the exhaust elbow is exposed to a corrosive environment. Since cast iron tends to expand in volume as a result of corrosion of its surface areas, water outlet openings intended to perform a draining function can be partially or fully closed as a result of corrosion. The insertion of a stainless steel tube in one or more water outlet openings of an exhaust elbow assures that an internal water cavity of the elbow can drain when the associated internal combustion engine is turned off, thereby minimizing the possibility of freeze damage to the exhaust components.
U.S. Pat. No. 6,645,024, which issued to Zumpano on Nov. 11, 2003, describes a fresh water marine engine flushing assembly and system. Fresh water is supplied from an onboard water supply which can also serve as the water supply for drinking, galley appliances, showers, toilets, etc. A path of fluid flow is disposed in fluid communication between the maintained water supply and the marine engine and communicates therewith by an adapter assembly which is preferably permanently secured to the marine engine. A flush valve assembly is remotely controlled and preferably electronically activated so as to regulate the flow of cooling water through the cooling system, in the conventional manner, or fresh water from the maintained water supply for purposes of removing salt water remnants and contaminants.
U.S. Pat. No. 6,912,895, which issued to Jaeger on Jul. 5, 2005, discloses a coolant flow monitoring system for an engine cooling system. The monitor is removably connectable in serial fluid communication with a coolant conduit of an engine cooling system. By providing a flow restrictor between upstream and downstream ports, a differential pressure is created between the upstream and downstream ports. The measured magnitude of this differential pressure allows a microprocessor, or similarly configured component, to determine the actual flow rate of the coolant passing through the coolant conduit between the upstream and downstream pressure sensing ports. In this way, actual flow is measured to indicate the proper operation of the cooling system.
U.S. Pat. No. 7,195,055, which issued to Jaeger on Mar. 27, 2007, discloses a device for connecting a secondary heat exchanger to an engine cooling system. The secondary heat exchanger device can be connected to a primary engine cooling system by providing a flow restrictor and upstream and downstream ports, wherein the flow restrictor is disposed between the upstream and downstream ports. A heat exchanger can be connected in fluid communication with the upstream and downstream ports to receive a flow of coolant liquid that results from a differential pressure between the upstream and downstream ports because of the pressure drop caused by the flow restrictor.
U.S. patent application Ser. No. 10/672,934, which was filed by Nakajima et al. on Sep. 26, 2003, describes a cooling system for a small watercraft. It prevents corrosion or freezing in a water channel. Water outside the watercraft is fed through a pump and piping or the like to an engine in the watercraft and cools the same and then is drained from the watercraft. Drain hoses are connected to portions of the engine and piping where water tends to remain and drain ports which are capable of being opened and closed are provided at the other ends of the drain hose. A single drain valve is provided at the drain port for opening and closing the drain hose.
U.S. patent application Ser. No. 11/445,348 (M10012), which was filed on Jun. 1, 2006, discloses a cooling system for a marine propulsion device. A cooling system for a marine vessel is configured to allow all cooling water to flow out of the cooling circuit naturally and under the influence of gravity when the marine vessel is removed from the body of water. All conduits of the cooling circuit are sloped downwardly and rearwardly from within the marine vessel to an opening through its transom. Traps are avoided so that residual water is not retained within locations of the cooling system after the natural draining process is complete. The opening through the transom of the marine vessel is at or below all conduits of the cooling system in order to facilitate the natural draining of the cooling system under the influence of gravity and without the need for operator intervention.
The patents described above are hereby expressly incorporated by reference in the description of the present invention.
Although many different cooling systems are known to those skilled in the art and each of those systems is typically provided with a procedure for draining water out of the systems when the marine vessel is not in use, these processes and procedures typically require manual intervention in one way or another. Some systems require that an operator remove a plug from a conduit to allow water to flow out of the cooling system. Some systems automatically allow the water to drain into the bilge of the marine vessel, but this requires a further intervention by the operator to remove the water from the bilge. The device described in U.S. Pat. No. 5,628,285 drains to the lower exhaust pipe. The connection to the lower exhaust pipe is below the waterline and therefore requires a seacock that is manually operated. Many of the draining systems described above are intended to simplify the effort required by the operator of a marine vessel when the water is to be drained from the system. However, they all require at least a minimum of effort. The Caldwell patent described above requires no intervention by an operator of a marine vessel when the marine vessel is taken out of the body of water in which it had been operating, but the Caldwell patent relates to a cooling system that comprises both an open portion and a closed portion. In that type of system, the engine is cooled by a coolant of a closed portion of the system. That coolant need not be drained at any time since, in most cases, the coolant is provided with an antifreeze liquid, such as ethylene glycol, which prevents it from freezing and causing damage. When a system, like that described in the Caldwell patent, automatically drains water from the cooling system of the marine propulsion device, it does not drain any coolant from the engine or heat exchanger portions of the system. However, many cooling systems for marine propulsion devices do not comprise closed portions for the engine cooling system. If the cooling system is completely open, water is circulated through the engine from the body of water in which the marine vessel is operating. Unlike the combined systems that are described in the Caldwell patent, completely open systems require that all of the water be drained from the engine and other related components when the marine vessel is taken out of the body of water. It would therefore be significantly beneficial if an open cooling system could be provided which automatically drains all of the water from the cooling system when the marine vessel is removed from the body of water without requiring any intervention of any is kind by the operator of the marine vessel. It would be particularly beneficial if the water is drained to a position outside the marine vessel via the inlet water path. In other words, it would be beneficial if the system could automatically drain all of its water as the marine vessel is simply removed from the body of water, placed on a trailer, and driven away.